Pneumatic converter



(No Model.)

' 4 Sheets-Sheet 2,- C. S. PRICE. PNEUMATIC GONVBRTER. N0. 554,457. Patented Feb. 11, 1896.

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PNEUMATIC CONVERTER. NO.- 554,457. 7 V Patented Feb. 11, 1896.

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0. S. PRICE. PNEUMATIC CONVERTER.

Patented Feb. 11, 1896.

INVENTOI? WITNESSES:

A ATTORNEY.

UNITED STATES PATE T OFFICE.

CHARLES S. PRICE, OF VVESTMONT, PENNSYLVANIA.

PNEUMATIC CONVERTER.

SPECIFICATION forming part of Letters Patent No. 554,457, dated February 11, 1896. Application filed April 10, 1895. Serial No. 545,224. (No model.)

To aZZ whom it may concern:

Be it known that I, CHARLES S. PRICE, a citizen of the United States, residing at WVestinont, in the county of Cambria and State of Pennsylvania, have in vented certain new and useful Improvements in Pneumatic Converters; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In the art of making steel by the pneumatic process it is customary to use a vessel ordinarily termed a converter, said vessel being provided with a removable bottom, in which are inserted a number of tuyeres composed of refractory material, each of said tuyeres being provided with a number of small holes extending throughout its length, through which air is forced from a blast-box forming the lower part of the bottom, said blast-box being connected to a suitable source of air supply, whereby air under considerable pressure is delivered to the lower part of the interior of the converter, where it comes into contact with the molten metal contained therein for the purpose of refining it.

Although the converter is lined with a refractory material, as is also the removable bottom section thereof, in which the aforesaid tuyeres are embedded, it is found in practice with the apparatus above described, which is the ordinary and usual one at present used, that its life is limited,owing to the fact that the combined effect of heat and chemical and mechanical action causes the refractory lining of the bottom and the tuyeres to be cut away, so reducing the thickness of the refractory lining at this point that the outer shell of metal-work which serves to hold the refractory material in position becomes endangered by the heat to such an extent that the bot tom has to be removed and replaced by another one previously prepared with a complete lining.

The ordinary life of a converter-bottom such as is described above from the causes mentioned is from fifteen to twenty heats, thus requiring many changes of these parts each day, when it is considered that in the ordidary steel plant from one hundred and thirty which are inserted in the same have been the subject of careful study for many years, little actual improvement has been made in this respect for some time, and the ordinary life of a bottom is as stated above.

In order that the bottoms of the present type shall be able to withstand the destructive action to which they are subjected, it is necessary that they be made of carefully-selected refractory material, in addition to which it is also very necessary that an eX- tremely high pressure of blast be used in order to keep the molten metal and slag in a state of suspension within the vessel, as near as possible, in order to prevent the cutting action of these molten materials upon the bottom.

Although the static pressure in an ordinary converter, due to the depth of metal, is only three or four pounds per square inch, it is found necessary to introduce air into the wind-box at a pressure not less'than eighteen pounds per square inch, and if for any reason, during the operation, this pressure is much reduced the bottom becomes rapidly destroyed, and the tuyeres are subjected to what is technically known as boring, the effect of which is to rapidly destroy them, the greatest wear in this case beginning at the upper surface of the holes within the tuyeres through which the air is introduced, this action being facilitated by a loss of pressure, as may be readily understood by one skilled in the art.

Owing to the short life and frequent changes necessary when using converter-bottoms as above described this item becomes one of considerable expense in' the conduct of steelworks, due to the fact that a large amount of refractory materials is daily consumed, requiring a large force of men to attend to the current repairs necessary on this account. In addition to this the use of suchbottoms necessitates a larger and more expensive plant than would be needed provided the bottoms could be made to last longer.

At present most converter plants are constructed with one or more spare converters in addition to the apparatus used in connection with the same, in order to provide for uninterrupted operation when the bottoms have to be changed.

It is one of the objects of my invention to provide a converter-bottom which will be less expensive to maintain owing to less wear of itsrefractory material and less expensive to operate owing to reduced pressure of blasts necessary to blow the heat. On account of its construction it will also be easier to change those parts which are destroyed or worn in service, for the reason that in my construction the wearing parts are small and light, and in most cases it will only be necessary to replace these smaller portions, leaving the main body of the bottom intact.

My improved converter-bottom consists -of an outer shell made in any convenient form for retaining refractory material,- said shell being provided around its upper periphery with suitable lugs or similardeviees, whereby the bottom may be properly secured to the lower section of a converter by means of keyed hook-bolts or other suitable devices. At one side of my bottom section I provide a metallie casing made in the general form of an elbow or T, said casing being lined with refractory material, in which is formed an opening leading from the upper portion of said elbow, when in an upright position, to the lower and lateral portions of the same, said opening connecting at its upper end with a suitable source of air supply and at its lower port-ion with a small opening made in the refractory lining of the bottom proper, said latter opening preferably expanding in width as it approaches the center of the converter.

At the upper part of the aforesaid elbow I place a tuyere-block, made of refractory material substantially rectangular in cross'section, provided with a large number of holes which register with the holes in the aforesaid elbow below and with the opening-in a suitable blast-pipe above. The position of this tuyere-block with respect to the level of the metal in the converter, assuming same to be in a quiescent state, the converter being in an upright position, is such that the lower surface of such tuyere-block is situated ata poi at about two-thirds of the distance from the bottom to the top of the metal-bath. This position within reasonable limits, however, is immaterial and I do not confine myself to the exact position shown or described. That part of the metal casing surrounding the tuyereblock may be so constructed as to readily allow withdrawing and replacing the same, which can be readily done, as this block is comparatively small. "he refractory lining of the elbow above'described is so constructed that at a point opposite the lower passage in same an opening is provided, which is closed by a suitable refractory plug so arrangedthat it can be readilywithdrawn and replaced for the purpose of inspecting or repairing that part of the refractory lining which can be reached from this point. The elbow is lined with refractory material and both it and the perforated tuyere-bloek are so designed and arranged that they can be readily disconnected from the other parts of the apparatus with which they coact and replaced by another or'others already prepared and held in readiness in case such change becomes necessary from anycause. The elbow and tuyere are so designed that a complete elbow, includin g a tuyere-block, or the latter only, in ay be easily renewed. The body of the bottom upon which the molten metal rests and impinges during the operation is in my construction made solid and without perforations for blast, wherein it is distinguished from the bottom in general use above described. By this construction I provide a solid mass of refractory material to receive the impact and fluxing action of the charge, while my tuyere-block is so situated that it is not ordinarily subjected to said destructive influences.

As the flow of air through passages such as are used in the tuyeres above mentioned varies as the square root of the absolute pressure, other things being equal, it maybe seen that from this cause the volume of air discharged at a pressure of nine pounds per square inch above the atmosphere would be about seventy percent. of that delivered at eighteen pounds per square inch above the atmosphere, but on account of the dili'erences of pressure in these twocases and consequent different densities the weight of air delivered at the lower pressure would be about seventytwo percent. of this amount. Thus practically fifty per centof the weight discharged at the higher pressure will be delivered at one-half that gagepressure, other conditions being similar.

On account of the fact that in my improved tuyere-bloek the holes can be greatly enlarged, as compared with the present usual construction, without endangering the safety of the refractory lining, thus reducing the frictional resistance, I propose, for example, to use in my tuyere-block a less number of holes than are used in the present type of bottom, but of greater diameter, in order to lessen the friction and the amount of work necessary to supply the same weight of airin a given time. In order to illustrate my meaning, I will give an example of this method of reducing the work necessary in supplying air, the weight of this supply remaining the same as in the present practice; butI do not limit myself totheexact proportions stated, as any other proportions may be used to produce a similar result in a greater or less degree, as may be readily understood.

The bottom of a twelve-ton converter as usedat present has sixteen tuyeres, each contaiuin g nineteen holes, each hole being threeeighths of an inch in diameter, or a total area of discharge through the tuyeres of thirty- ICC three square inches, to which air is supplied at eighteen pounds gage-pressure per square inch.

A tuyereblock of my construction to supply the same weight of air in the same time at one-half the above pressure would only need to have one hundred holes, each threefourths of an inch in diameter, and in consequence of this construction the work of furnishing the blast under these conditions would be very much reduced. In this calculation no account is taken of the difference in length between tuyeres of the two different types under consideration; but in this respect my tuyere-block has an additional advantage not shown in the above calculation, in that it is much shorter than the present usual form of tuyere and thereby offers less frictional resistance to the passage of' air through it.

Having given this general description of my invention, I will now refer to the annexed four sheets of drawings, which form part of this specification, and in which like letters refer to like parts.

Figure l is an elevation of the exterior of a converter, showing my new bottom section in place. Fig. 2 is a vertical section taken on the line 2 2 of Fig. 1. Fig. 3 is a sectional plan, the section being taken on a horizontal plane just above the body of the bottom shown in Fig. 2, while the upper part of the tuyereblock and a part of its casing are shown in plan, and that part of the casing surroundin g the tuyere-block is shown in section. Fig. 4 is a sectional elevation taken 011 the line at 4 of Fig. 2. Fig. 5 is a vertical crosssection through the central line of that part of the apparatus shown in Fig. 4, this section, however, being taken on a plane at right angles to that of the latter figure, and also showing a slightly -modified form whereby the tuyere-block may be readily withdrawn. Fig. 6 is a vertical section through the center ofa converter, showing another form of my improved bottom which is somewhat different from that shown in the preceding figures. In this view the upper part of the converter is not shown, as it is unnecessary for the purpose of this illustration. Fig. 7 is a horizontal section taken on the line 7 7 of Fig. 6.

In the different figures, A represents the central body or shell of a converter, and B is the refractory lining of the same.

0 is the main outer shell of the bottom, and I) the refractory lining thereof.

E E are the trunnions, and F is the bottom casting, which is secured to the bottom shell, 0, and which serves as a stand upon which to support the bottom when being repaired or handled.

G is the outer shell of my improved form of blast-nozzle, secured to the body of the bottom 0 by the bolts (1 (Z. H is the refractory lining of said nozzle, and I is a refractory plug which serves to close the outer opening in the refractory lining H.

I is a cover-plate removably secured to the shell G by the bolts e e for the purpose of holding the plug I in position, as shown in Figs. 2, 5, 6, and '7.

K is a tuyere-block provided with numerous small holes h 71 h, said tuyere-block being held in position by the shell .I, which lat ter is secured to the elbow Gand to the telescopic portion of the blast-pipe L by the bolts f f and g g, respectively, and in the modified form shown in Fig. 5 the bolts f f serve a similar purpose.

M is a blast-pipe provided with an expansion-joint 01": the usual form at its lower end in order to provide for any inequalities in fitting up the bottom section in connection with the body of the converter or in fitting the elbow-section G in connection with the bottom section and the blast-pipe, as may be readily understood.

The blast-pipe M is fitted to the trunnion E, as shown, and is provided with a number of small holes '6 i, which register with the holes j j of the body of the trunnion and through which air is supplied to said blastpipe M through the blast-nozzle 76, said blastnozzle being connected with a suitable source of air supply and so fitted within the trunnion E that the latter may revolve without breaking the connection between it and the blast-pipe 7r, after the usual manner of such constructions.

O is the central trunnion-ring of the converter, provided at its top and bottom with the rings N N.

N N and N N are brackets secured to the inner central shell of the converter and to the trunnion-ring O by means of the bolts P P.

o is the bottom ring of the central converter-shell, A, to which ring are attached the hook-bolts a, said hook-bolts being secured by the keys I) to the lugs a of the bottom shell, 0, thus serving to hold said bottom section in place against the body of the converter.

Between the refractory lining B of the 0011- verter proper and the refractory lining D of the bottom section is interposed a layer of plastic refractory material d, which serves to make a tight joint between the sections.

F of Fig. 6 is the lower portion of a modified form of bottom section, said lower part being similar to that known as the outer shell of the wind-box of the old or usual type of construction at present, the modified form shown in Fig. 6 being so arranged as to utilize bottoms of present form with only a slight change and the addition of my improved blast-nozzle, as may be readily understood by one skilled in the art.

The arrangement and proportions of the lower lateral portion of the blast-opening at and near the point where it enters the body of the converter in my improved section are such that when the vessel is turned in either direction upon its side in position .to receive or discharge molten metal there is no possibility of the opening becoming fouled by said metal or other material, for the reason that as the converter is turned such material is naturally diseh arged from said opening by the force of gravity, as maybe readily understood by reference to the drawings accompanying and forming a part of this specification.

I am aware that pneumatic converters have been designed and proposed in which the air is supplied to the body of the metal-bath in one portion of the vessel, said blast being first directed downward and proceeding thence upward through the main body of the metal, the opening in which the blast is first introduced being separated from the body of the converter by a refractory diaphragm, and I do not claim such construction broadly, but

hat I do claim, and desire to secure by United States Letters Patent, is

1. In a pneumatic converter, a bottom sec tion lined solidly in its lower portion with refractory material, provided with a side blastinlet at or near the upper surface of said bottom-lining, and a removable elbow lined with refractory material in which is formed part of the blast-inlet, said latter portion of the blast-inlet being connected at one end to a suitable blast-pipe an d at'the other to the main body of the bottom, said elbow being removably secured to said bottom and blast-pipe by suitable bolts, substantially as described.

2. In a pneumatic converter, a bottom section lined solidly in its lower portion with refractory material, provided with a side blastinlet formed partly in the side lining of said bottom, this portion of the inlet'increasing in width as it approaches the center of the bottom, and a removable easing lined with refractory material forming part of the blastinlet and connecting the lower lateral portion of the same to a suitable blast-pipe, said casing being removably secured to said bottom and blast-pipe by suitable bolts, substantially as described.

. 3. In a pneumatic converter, a bottom section lined solidly in its lower portion with refractory material, provided with a side blastinlet at or near the'uppersurface of said bottom-lining, and a removable casing lined with refractory material forming part of the blastinlet, connecting the lower lateral portion of the same to a' suitable blast-pipe and being provided near the junction of said blast-pipe and said casin g witha perforated tuyere-bloek of refractory material, substantially as set forth.

4. In a pneumatic converter, a bottom section lined solidly in its lower portion with refractory material, provided with a side blastinlet formed partly in the side of said bottom, a removable casing lined with refractory material formingpart of said blast-inlet and connecting the lower lateral portion of the same to a suitable blast-pipe, said inlet being provided with a removable plug of refractory material located opposite its lower lateral opening to allow access to same and its connecting-passages, substantially as set forth.

5. In a pneumaticconverter, a bottom section lined with refractory material, and a side blast-inlet formed in the side lining of said bottom and connected to a suitable source of air supply, by means of an elbow lined with refractory material and provided at or near its upper end with a perforated tuyere-block, said tuyere being so arranged as to be readily removed and replaced, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

CHARLES S. PRICE. iVitnesses ELsIE W'EIMER, CYRUS ELDER. 

